1. Field of the Invention
This invention relates in general to a semiconductor apparatus designed to operate as a bipolar transistor and particularly to a semiconductor apparatus suitable for high output and high frequency.
2. Description of the Prior Art
The prior art bipolar transistor used as a circuit element of a semiconductor integrated circuit is formed in a socalled lateral structure and has an emitter region, a base region and a collector region which are respectively located for easy manufacture and simplicity of wiring. However, the prior art bipolar transistor using such lateral structure generally has a small current amplifiction factor .beta. which is a disadvantage.
The assignee of the present invention has previously proposed a novel semiconductor apparatus which is formed in a lateral structure and which can carry out bipolar transistor operation with a large current amplification factor .beta. which is disclosed in published Japenese patent application which has been unexamined and is identified as number 224841/1983. FIGS. 1 and 2 of the present application illustrate an example of such semiconductor aparatus.
FIGS. 1 and 2 disclose the previously proposed semiconductor apparatus which is formed such that on one major surface 1a of a semiconductor substrate 1 having semi-insulating property there is formed a first region 2 of, for example n.sup.+ conductivity type which will become an emitter region. A second region 3 of n.sup.+ conductivity type which will become a collector region is formed in the substrate 1 and is spaced apart from the region 2. A third region 4 of p.sup.+ conductivity type is formed betwen the regions 2 and 3 as illustrated. Emitter electrode 5 is formed on the emitter 2, a collector electrode 6 is formed on the collector region 3 and a base electrode 7 is formed on the region 4. With the arrangement illustrated in FIGS. 1 and 2, when a forward biasing voltage is applied between the first and third regions 2 and 4, holes will be injected with high concentration from the third region 4 into the region of the semi-insulation semiconductor substrate beneath the third region 4 so as to form an imaginary base region 8 in such region as indicated in dashed line FIG. 1 and electrons injected from the first region 2 are introduced through the imaginary base region 8 to the second region 3 which is biased in the positive directions so that the semiconductor apparatus will operate as a bipolar transistor of the n-p-n type.